Tour de France: Daryl Impey tests positive for masking agent

South African cyclist Daryl Impey was a major part of Orica-GreenEdge's Tour de France challenge. Photograph: Doug Pensinger/Getty Images

Orica-GreenEdge manager Shayne Bannan has defended the team's anti-doping regime, saying they have nothing to hide.

He has also called on his Tour de France riders to stay focussed in the wake of the news that team-mate Daryl Impey is embroiled in a doping scandal. Impey is off the team roster while he deals with a positive test for the masking agent Probenecid.

Bannan said Impey initially told him of the positive A sample last week and confirmed on Tuesday that the B sample result had also come back positive.

"Obviously the guys will be affected by what's happened, because of the friendship within the team," Bannan said. "How deep of an effect, we're really not too sure. It's really important that we stay focussed – we have absolutely nothing to hide. We can be proud of our short history in the sport. It's a matter of really just continuing the ethics that we stand by."

Impey's positive test has a massive impact on several fronts for Orica-GreenEdge. It is a major blow to the image of a team that commissioned anti-doping consultant Nicki Vance to conduct an independent review of their operations and staff in the wake of the Lance Armstrong scandal.

Impey's positive test comes nearly a year after popular Orica-GreenEdge veteran Stuart O'Grady retired and then within a few days confessed to doping once in the late 1990s. That revelation left his lofty reputation in tatters.

The timing of the news about Impey also could not be worse, given this year's Tour starts on the weekend in England.

Orica-GreenEdge are in for some torrid media scrutiny at the Tour. Apart from being an important member of the team, Impey is also one of their most popular riders. Team leader Simon Gerrans famously gave up his yellow jersey last year so Impey could take over as the Tour leader in the opening week.

Bannan did not want to comment about the specifics of Impey's case, but defended the South African's character. "Certainly in the time Daryl has been with us ... he has had a clean record, he's an honest guy," he said.

The Orica-GreenEdge general manager also questioned why it took so long for Impey to become aware that his A test sample had gone positive. The test was taken on at the South Africa championships on February 6, but Impey said he was not told of the positive result until 23 June.

"I'm not sure why – it does seem a long time," Bannan said. "I would imagine that's one of the questions Daryl and his legal team will be asking."

Regardless of what happens, Bannan said the news is a setback as cycling tries to rebuild its reputation in the post-Armstrong era. But Bannan said cycling was now dealing with isolated cases, not the systematic team doping that plagued men's professional ranks in the 1990s.

"No question, this is disappointing for the sport," he said. "But we'll continue to be transparent and we'll continue our education of the athletes."